Catalytic cellulignin fuel

ABSTRACT

A catalytic cellulignin fuel obtained by a biomass pre-hydrolysis process and that is composed of cellulose and globulized lignin with a specific surface of about 1.5-2.5 m 2 /g. The cellulignin fuel may be ground down to particles smaller than 250 μm and has a combustion heat value that can reach up to 18-20 MJ/kg and an ignition time equal to or shorter than 20 ms (0.02 s).

FIELD OF THE INVENTION

The present invention relates to a new fuel obtained from biomass.

BACKGROUND OF THE INVENTION

The energy obtained from biomass is highly positive from the point ofview of energy. For instance, the energetic efficiency of the so-calledshort-rotation biomass is 89.5%. and the rate of liquid energy is 9.48times higher. However, in spite of this fantastic energetic efficiency,biomass cannot compete with fossil fuels due to the high costs resultingfrom the large number of steps required to produce it and also due tothe difficulty in handling the raw biomass, which renders it not verypractical.

The following points related to the process for producing biomass shouldbe taken into account: 1) planting and cultivation (propagation); 2)expenses with nutrients (fertilization); 3) exposure to the sun; 4)temperature; 5) precipitation; 6) conditions of soil and water, 7)harvesting method; 8) resistance to diseases; 9) competition in the areawith production of foodstuffs, pastures and fibers; 10) areaavailability; 11) transport of the raw biomass.

Biomasses are composed of cellulose, hemicellulose and lignin, thecomposition position being exemplified in Table 1, and microstructureaccording to FIG. 1.

TABLE 1 Typical Composition - Pine Tree (%) Cellular wall hemicellulosecellulose lignin LM - middle lamella — — 3.0 P - primary wall 1.4 0.78.4 S - secondary wall S1 3.7 6.13 10.5 S2 18.4 2.7 9.1 S3 5.2 0.8 Total28.7 40.3 31.8

The cellular walls are composed of macrofibrillae, microfibillae,micellae and cellulose molecules. The nuclei of the cells (cytoplasm) iscomposed of aqueous solutions. The following formulas represent theapproximate estimates of the specific surface (area per unit of mass) ofthe biomass in the hypothesis of its microstructure being completelyreleased.

1—Geometry with a Square section and length l (S and M: cell surface andcell mass).${S = {4\quad b\quad l}};{M = {{{4\quad b\quad l\quad e\quad\rho}\therefore\frac{S}{M}} = {\frac{4\quad b\quad l}{4\quad b\quad l\quad e\quad\rho} = \frac{1}{e\quad\rho}}}}$$\begin{matrix}{{broadness}\quad{of}\quad{the}\quad{cell}} & {b = {10\quad{µm}}} \\{{thickness}\quad{of}\quad{the}\quad{cell}\quad{{wall}:}} & {e = {1.0\quad{µm}}} \\\quad & \begin{matrix}{\rho = {1.5\quad g\text{/}{cm}^{3}}} \\{= {1.5 \times 10^{6}\quad g\text{/}m^{3}}}\end{matrix}\end{matrix}$

2. Specific area of the macrofibrillae, microfibrilla, miscellae andcellulose molecules.${S = {\pi\quad\phi\quad l}};{M = {{{\frac{\pi\quad\phi^{2}}{4}l\quad\rho}\therefore\frac{S}{M}} = {\frac{\pi\quad\phi\quad l}{\frac{\pi\quad\phi^{2}}{4}l\quad\rho} = \frac{4}{\phi\quad\rho}}}}$

2.a—Specific area of the macrofibrilla (φ=50 nm; Macropores>50 nm)$\frac{S}{M} = {\frac{4}{50 \times 10^{- 9} \times 1.5 \times 10^{6}} = {53\quad m^{2}\text{/}g}}$

2.b—Specific area of the microfibrillae (φ=50/4=12.5 nm; Mesopores 2nm<φ<50 nm)$\frac{S}{M} = {\frac{4}{12.5 \times 10^{- 9} \times 1.5 \times 10^{- 6}} = {213\quad m^{2}\text{/}g}}$

2.c—Specific area of the miscella (φ=(12.5/4)nm=3.1 nm; Micropores φ<2.0nm)$\frac{S}{M} = {\frac{4}{3.7 \times 10^{- 9} \times 1.5 \times 10^{6}} = {860\quad m^{2}\text{/}g}}$

2.d—Specific area of the molecules of cellulose (3.1/6)nm=0.517 nm)$\frac{S}{M} = {\frac{1}{0.517 \times 10^{- 9} \times 1.5 \times 10^{6}} = {1290\quad m^{2}\text{/}g}}$$\begin{matrix}{{N = {{1 + {6{\sum\limits_{0}^{n}{n\quad i}}}} = 1}},\left( {{1 + 6} = 7} \right),\left( {{1 + 6 + 12} = 19} \right),} \\{\left( {{1 + 6 + 12 + 18} = 37} \right).}\end{matrix}$

The theoretical specific area for the cell is of about 0.7 m²/g, ofabout 50 m²/g for the macrofibrillae, of about 200 m²/g for themicrofibrillae, of about 900 m²/g for the miscealla, and of about 1300m²/g for the molecules.

As far as solid fuels are concerned, their conventional combustioncomprises 5 zones: first non-reactive solid zone (heating and drying),second reaction zone of condensed phase (solid pyrolysis), thirdreaction zone of gaseous phase (pyrolysis of gaseous phase andoxidation), fourth primary combustion zone (gaseous phase), fifthpost-flame reaction zone (secondary combustion). The specific kineticsand reactions of each zone is not completely known yet.

FIG. 2 illustrates the conceptual model of conventional combustion forwood. Wood is anisotropic and hygroscopic, and its fibers (tracheids)are hollow and have a length of from 3.5 to 7.0 mm in soft wood, andfrom 1 to 2 mm in hard wood. The linked water is of about 23%, and thetotal moisture reaches 75%. Cellulose, hemicellulose and lignin behaveas polyalcohols wherein the main functional group is the OH group.Cellulose is a linear polysaccharide of anhydrous glucose with 1→4-βglucoside bonds. After oxidation, the functional groups are carbonylic,ketone and carboxylic groups. On the other hand, hemicellulose is apolysaccharide with branched chain, the main components of which are4-O-methylglucoroxylanes in hard wood and glucomanes in soft wood. Themain functional groups thereof are carboxylic, methylic and hydroxylicgroups. Lignin, on the other hand, is a tridimensional backbone of 4 ormore substituted phenylpropane units. The basic constitutive blocks areguayaquil alcohols (soft wood) and seringyl alcohol (for the two typesof wood), and the dominant bonds are β-O-4.

The structures of cellulose and lignin are highly oxygenated and thelocation of the functional groups is useful in understanding themechanisms of pyrolysis and oxidation.

For the purpose of comparison, it is observed that the structure of themineral coal is aromatic, it has few hydroxylic functional groups andβ-O-4 bonds. Nitrogen and sulfur are part of the structural rings withlittle nitrogen existing in the amine form. The fact that the oxygencontent is very low in coals when compared with wood is highlysignificant, since it imparts greater reactivity to the latter.

In the conventional combustion of wood the drying stage involves, infact, 4 steps, namely 1) energy required for heating the wood up to 100°C. (373° K)=0.08×100×(1−TU) kJ/kg, wherein TU is the moisture content(percentage); 2) energy required for heating water=4.2×100 kJ/kg; 3)energy required for vaporizing the water=2.26 MJ/kg; and 4) energyrequired for releasing the linked water 15.5×TU kJ/kg (average). Thepredominant value is the energy from vaporization of water.

The heating stage comprises three factors that have significantinfluence: the first one is the energy for heating up to the pyrolysistemperature (500-625° K); the wood specific heat is 1113 J/g at 273° Kand 1598 J/g at 373° K, while the specific heat of the wood with 35% ofmoisture is 2.343 J/g at 300° K. Secondly, there is the influence of themoisture preventing the particle core be heated up to the temperature atwhich water is evaporated and establishing the reaction states. Thethird factor of influence is the moisture in the increase of the thermalconductivity of the wood particle, which may at most double its value.In addition to its influence on the drying and heating, moisture alsocauses significant effects on the solid state pyrolysis.

The next stage is the solid pyrolysis step. In this combustion zone,reactions of cleavage of the molecules into gaseous fragment andcondensation reactions prevail, whereby coal is produced (tar resultinginto 3 final fractions: a gaseous one, a liquid one, and a solidone—coal). The pyrolysis temperatures are: hemicellulose (500-600° K),cellulose (600-650° K) and lignin (500-773° K). Table 2 show thepyrolysis products from cellulose and xylan, with a high tar contentthat causes a secondary combustion close to the oils for the wood.

TABLE 2 Pyrolysis Products from Cellulose (873° K) and Xylan (773° K)Product Cellulose (% P) Xyilan (% P) Acetaldehyde 1.5 2.4 AcetonePropinaldehyde 0.0 0.3 Furanics 0.7 Tr Propenol 0.8 0.0 Methanol 1.1 1.32-Methylfuran Tr 0.0 2,3-Butanedione 2.0 Tr 1-Hydroxy-2-Propan glycoxal2.8 0.4 Acetic acid 1.0 1.5 2-Furaldehyde 1.3 4.5 5-Methyl-2-Furaldehyde0.5 0.0 CO₂ 6.0 8.0 H₂O 11.0 7.0 Coal 5.0 10.0 Tar 66.0 64.0 Tr = trace

The opening of aromatic rings is an intermediate step in forming thevolatile material, generating acetic acid and acetaldehyde, which aredecomposed by decarboxylation of acetic acid (CH₃COOH→CH₄+CO₂) anddecarbonilation of the acetaldehyde (CH₃CHO→CH₄+CO). From thehemicellulose, the resulting product is C₂H₄ and CO from the propanol.In the next zones, there will be sequence in the pyrolysis andoxidation, giving CH₄, C₂H₄, CO and CO₂ as final products.

The pyrolysis of lignin is different in comparison with thehemicellulose and cellulose and at 823 K it produces the followingcomponents: coal (55%), gaseous fraction (45%) composed of CO (50%) CH4(38%), CO2) 10%) and C2H6 (2%). The tar is composed of phenylacethylene,antracene and naphthalene. Table 3 shows the formation of coal in thepyrolysis of several different materials.

TABLE 3 Coal Formation in the Pyrolysis of Several Different Materials(673 K) Material Coal (% P) Cellulose 14.9 Poplar (wood) 21.7 Larch(wood) 26.7 Aspen (branches) 37.8 Douglas (bark) 47.1 Klason Lignin 59.0

Moisture also has a considerable influence on the particle pyrolysissince it causes an enormous difference in temperature between theparticle core and the periphery thereof (400° K), creating a physicalseparation between the heating and drying zone and the pyrolysis zone.The dominant influence of moisture is to reduce the flame temperature ofthe burner, directing the product to coal formation and reducing therate of pyrolysis. The theoretical flame temperature of the woodcombustion is given by:T _(a)=1920−(1.51[TU/(1−TU)]×100)−5.15 X _(exAr)

wherein Ta (K) is the adiabatic flame temperature, TU is the fraction ofthe moisture contents, and X exAr is the percentage of air excess. Inaddition to the reduction of the adiabatic temperature, there is anincrease in the air excess, given by:X _(exAr)(%)=40[TU/(1−TU)]

For TU>33%, T_(a)=1740° K and for TU=50%, T_(a)=1560° K and consequentlythere is a decrease in the volatile content and an increase in the coalcontent. Finally, one should cite that the ashes reduce the localtemperature and catalyze the formation of coal.

Next, the pre-combustion reaction occurs, which represent the cleavageof volatile material into fragments of radicals dominated by reactionsof initiation of chains of the type:R−R→R+R′(368 kJ/mol)R″−H→R″+H(410 kJ/mol)wherein R=C₂H₆, CH₃, etc. e R″=methylic group.

In wood, the first reaction is most probable due to its lower energy,and an example thereof is given below:C₂H₆+M→2CH₃+M2CH₃+2C₂H₆→2CH₄+2C₂H₅M+C₂H₅→H+C₂H₆+MH+C₂H₆→H₂+C₂H₅

wherein M is a heat (ash or vapor)-removing particle or molecule. If R″contains two or more carbon atoms, the C—C bond is broken preferablyinstead of the C—H bond. In addition to the reactions of chaininitiation, the pre-combustion zone includes reduction reactions withrecombinations of radicals R+R′→R−R′, especially if the pre-combustionzone is spatially broad. An example thereof is the recombination ofnitrogen forming N₂ instead of NO_(x).

After the pre-combustion reactions, primary combustion reactions occuroxygen and fuel mixed in the primary combustion zone results in a numberof reactions of free radical, producing CO₂ and H₂O.RH+O₂→R+HOOCH₃+O₂+M→CH₃O₂+MCH₃O₂→CH₂O+OH

HCO and CO (CH₂O+(1/2)O₂→HCO+OH or CH₂O+O₂→CO+2HO) are formed from CH₂O,and their concentration is maximized at flame temperatures of 1320 K,which is the wood combustion temperature.

Finally, the post-combustion reactions occur: the processes of woodcombustion occur at low temperature, and reactions of chain end occur inthe secondary combustion. The hydroxyl radical (CH₂O) is of greatsignificance when it is present at high concentrations. The main endreactions are:HCO+OH→CO+H₂OCO+OH→CO₂+HCO+O₂→CO₂+O

the latter being of lesser importance in this zone. The CO₂ productionfrom CO is controlled by the OH concentration, which is relatively highfor low temperature systems (wood). It follows that the chain end is therecombination of H and OH groups aided by heat-removing species (M). TheC:H ratio is relatively high for soft wood (1:1.45) and hard wood(1:1.37) compared with mineral coals (1:017). The wood solid pyrolysisproduces water, CH₄, C₂H₄, and C₂H₆, resulting in a substantial amountof hydrogen in the volatile gases to increase the concentration ofhydroxyl radical for a complete and rapid oxidation (greaterreactivity). There is no complete expressions in the literature for thissystem, due to the large number of variables associated to the oxidationof the wood volatiles.

In the combustion of (wood) charcoal, the charcoal obtained from thepyrolysis is porous and contains various free radicals for O₂ attack. Inaddition, it contains oxygen and hydrogen, its empirical chemicalformula being C6.7H,3.3O. Three mechanisms were proposed for thecharcoal oxidation, it being recognized that the combustion rate islimited by the sites of free radicals on its surface. The charcoaloxidation is also limited by the mass transport. The first mechanism isthe Boudouard, as the general indicator of charcoal combustion.C+O₂→2CO

This reaction is highly endothemic with the following reactionconstants: 1.1×10⁻² (800° K) and 57.1 (1200°). The CO released isvolatile and its combustion is completed in the flame out of theparticle. The second mechanism is the chemical adsorption of O₂ directlyon the coal. The activation energy of the O₂adsorption on the poroussurface of the coal ranges from 54 kJ/mole to 10 105 kJ/mol,respectively, for chemically adsorbed quantities from zero to 2.5 molesof O₂ per gram of coal. The chemical adsorption reactions are:C*+O₂→C(O)*→C(O)_(m)→CO+CO₂C*+O₂→CO_(es)→CO+CO₂

The asterisk indicates an active site of reaction, m stands for moveablespecies, and es stands for stable species. The charcoal active sites canbe generated by the mechanism of pyrolysis. The third mechanism ofcharcoal oxidation involves reactions of hydroxyl radicals in the activesites given by:2OH+C→CO+H₂OOH+CO→CO+H

Hydroxyl radicals are internally generated by homolytic cleavage of thevarious hydroxylic functional groups existing in the wood ordissociation of the moisture released by the fuel. The moistureinfluence on the coal oxidation are not well known, as in the case ofthe pyrolysis of wood. It is speculated that the moisture “deletes” thesites, reducing the rate of coal oxidation. The presence of moisturedelays the rate of oxidation of charcoal.

In short, the wood combustion is a multistage process that involvesheating and drying, solid state pyrolysis, producing volatile compoundsand coal, reactions of gaseous phases (pre-combustion, primarycombustion and post-combustion) and combustion of the coal. The variousfunctional groups existing in wood generate a significant number ofvolatile products from the solid pyrolysis of particles, the variousfunctional groups and the high aliphatic contents increasing thereactivity of wood, contributing to the high proportion of flames in thecombustion of the wood with respect to mineral coal. The moistureincreases the thermal conductivity, results in greater production ofcoal in the solid state pyrolysis, increases the concentration ofhydroxyl groups for the reactions of gaseous phase and of the coal, andreduces the oxidation rate of the coal, decreasing its temperature and“deleting” the reactive sites.

In view of the complexity and the operational disadvantages presented bythe conventional combustion processes, it was desirable to develop a newfuel from biomass that could meet the essential requirements ofcombustion and overcome the technical drawbacks of the known fuels.

In this regard, various studies have been carried out for thedevelopment of new fuels from biomass and some attempts have alreadypresented satisfactory results, as in the case of a cellulignin fuelmentioned in the article “Cellulignin: a new thermoelectric fuel” byDatro G. Pinatti, Christian A. Vieira, Jose A. da Cruz and Rosa A.Conte, which relates to a product from generic cellulignin obtained by aprocess of pre-hydrolysis of biomass without optimized control. However,it was still desired to obtain a fuel that would present even moreadvantageous results, mainly from the economic point of view and theapplications thereof in the main thermoelectric technologies: ovens,boilers, gas turbines and generation of energy by hydrodynamic magnet(MHD).

Therefore, the objective of the present invention it to provide a newcellulignin fuel with catalytic properties that will meet these marketrequirements with improved combustion characteristics.

SUMMARY OF THE INVENTION

The present invention relates to a catalytic cellulignin fuel that iscomposed of cellulose and globulized lignin and that presents a specificsurface of about 1.5-2.5 m²/g, with an average value of 2.0 m²/g.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of the biomass cellular structure.

FIG. 2 shows the steps of the conventional combustion process of solidfuels.

FIG. 3 a shows a microphotograph of the structure of a celluligninaccording to the present invention (with an increase of 1000 times).

FIG. 3 b shows a microphotograph of the structure of a celluligninaccording to the present invention (with an increase of 10,000 times).

FIG. 3 c shows a microphotographs of the structure of a celluligninaccording to the present invention (with an increase of 50,000 times).

FIG. 3 d shows a microphotograph of the structure of a celluligninaccording to the present invention (with an increase of 100,000 times).

FIG. 3 e shows the microstructure of the cellulignin with globlizedlignin according to the present invention (370 nm).

FIG. 3 f shows the microstructure of the cellulignin with globlizedlignin according to the present invention (133 nm).

FIG. 3 g shows the microstructure of the cellulignin with globlizedlignin according to the present invention (333 nm).

FIG. 3 h shows the microstructure of the cellulignin with globlizedlignin according to the present invention (33 nm).

FIG. 4 a graphically shows a difratogram of an X-ray for wood andcellulose (Core).

FIG. 4 b graphically shows a difratogram of an X-ray for wood andcellulose (Abrumum).

FIG. 4 c graphically shows a difratogram of an X-ray for wood andcellulose (Cellulose).

FIG. 4 d graphically shows a difratogram of an X-ray for celluligninhydrolyzed in woodshaving.

FIG. 4 e graphically shows a difratogram of an X-ray for celluligninground in knif mill.

FIG. 4 f graphically shows a difratogram of an X-ray for celluligninground in ball mill.

FIG. 5 shows a graphic of the enthalpy variation for the reactants in aprocess of catalytic combustion of coal, and

FIG. 6 shows ratio of the burning time of mineral coal to the particlesize.

FIGS. 7 a and 7 b in turn shows the power irradiated in the combustionof cellulignin according to the present invention.

FIGS. 8-12 b illustrate systems and equipment useful for the combustionof the cellulignin fuel now defined. FIG. 8 illustrates a CatalyticCellulignin feeding system. FIG. 9 illustrates a helical feeder. FIG. 10illustrates a rotary valve. FIG. 11 illustrates an axial combustor. FIG.12 a illustrates a horizontal combustor. FIG. 12 b illustrates avertical combustor.

DETAILED DESCRIPTION OF THE INVENTION

After detailed studies, the inventors achieved a catalytic celluligninfuel obtained from biomass, which allows a surprising result regardingits combustion. The catalytic cellulign fuel of the invention isprepared by a process of pre-hydrolysis of biomass using a reactor suchas described in the Brazilian patent application filed on this same datefor “An Apparatus and Process of Pre-Hydrolysis of Biomass”. Thereferred-to pre-hydrolysis may be carried out for any type of biomass,such as wood, sugar-cane bagasse and straw, vegetable residues, barks,grass, organic part of garbage, etc.

The pre-hydrolysis process described in the above-mentioned patentapplication generically comprises steps of discharging the biomass in ahelical feeder, in the device of pre-hydrolysis of biomass, followed bya pressurization operation comprising the following steps: 1) fillingthe device of pre-hydrolysis of biomass with a pre-heated acidicsolution; 2) heating; and 3) pressurization, said process beingdistinguished by the fact that the prehydrolysis is carried outsimultaneously with a rotary oscillation of the biomass pre-hydrolysisapparatus, purging of the vapor and controlling the temperature,pressure, acid contents, pre-hydrolysis time, and liquid/solidrelationship, monitoring the sugar contents until a value of about 10Bricks is reached by means of a sugar-measuring device. Then, the stepsof discharge of the pre-hydrolyzate into a tank through aheat-exchanger, sugar-recovering washing; and discharge of thecellulignin into mechanical washers or carriages to be washed bypercolation are carried out.

Again referring to FIG. 1 and Table 1 presented above, one can see thataccording to the processes of hydrolysis of biomass the cellulose fibersrelease is not complete, because the hemicellulose has its highestconcentration in the second layer (S2) of its secondary wall. With thepre-hydrolysis process developed by the present inventors, it now hasbeen achieved a product with a specific surface of about 1.5-2.5 m²/gwith an average value of 2 m²/g measured by BET (Brunace, Emmett andTeller) and a slush number 100, this meaning that this pre-hydrolysisprocess reaches the level where partial release of the macrofibrilleoccurs.

The confirmation of this macrofibrillae release is illustrated in themicrophotographs presented in FIGS. 3 a-3 e. FIG. 3 a shows themicrostructure of the catalytic celllignin according to the inventionafter pre-hydrolysis, with an increase of 1000 times (scale of 10 μm).FIG. 3 b shows a cellular wall presenting the middle lamella with anincrease of 10,000 times (scale 1 μm), while FIG. 3 c shows the cellularwall with an increase of 50,000 times (scale 100 nm) and FIG. 3 d showsthe cellular wall with an increase of 100,000 (scale of 10 μm). FIG. 3 eshows the microstructure of a second sample where it is possible toobserve the lignin globulization.

The combination of an open structure, while maintaining the crystallinecharacteristics of cellulose demonstrated by X-rays diffraction, as canbe seen in FIG. 4, enables one to achieve the following characteristicsof the cellulignin fuel:

1—due to the maintenance of the cellulose crystalline characteristics,it is possible to effect the grinding of the cellulignin according tothe present invention down to below 200 μm by using hammer mills withoutthe need for intermediate sieving and with a low energy consumption(about 12 kWh/t). Due to this characteristic, the new fuel is called“catalytic” lignin.

2—Easy drying of the water in rotary dryers, ovens or cyclones: thecellulignin according to the invention, which has particle size below200 μm, presents a completely open structure which permits it to bedried at 500 ppm of moisture and at low temperature, that is to say, at125° C. (temperature of chimney gas).

The water contained in biomass is one of the worst characteristics forcombustion and the drying achieved for the cellulignin of the inventionallows the obtention of a value of 18^(A) 20 MJ/kg for the combustionheat, which is the double of the combustion heat of biomass with normalmoisture of 45%.

Therefore, one of the great technical advantages obtained by the presentinvention is that the catalytic cellulignin may be externally dried withthe heat of the chimney gas and subsequently burned in dry form. Thisoption is unfeasible for raw wood.

3—When in the powder form, the cellulignin density is of 600 kg/m3 inthe so-called accommodated form, and 450 kg/m3 in the non-accommodatedform. This represents an average energetic density of 20 MJ/kg×500kg/m3=104 MJ/m3, compared with the energetic density of 40 MJ/kg×800kg/m3=3.2×10⁴ MJ/m3 for fuel oils, which means that the tanking andhandling of the catalytic cellulignin fuel are only three times as highas those of fuel oils, and it is drastically easier than the handling ofraw biomasses (wood and vegetable residues), which require large volumesand huge equipment.

4—The dosage of the cellulignin of the invention in combustion apparatusis made, for instance, by means of helical dosing device or rotaryvalves and the feeding of air such as drag-gas air in the proportion ofair:cellulignin of about 3.28:1 by weight and 1261.6:1 by volume. Thisimparts to the cellulignin a characteristic equal to that of the gasesor liquids in the operations of dosing and feeding, providing adrastically easier operation than the conventional dosing and feeding ofsolid fuels, especially biomasses.

5—The microstructures pictures show the disclosure of the microfibrillaein a dimension of 50 nm. This technique establishes the correlationbetween the process (hemicellulose digestion) and the product (openstructure with medium specific surface). It constitutes one of the mainnew characteristics of the product, as well as the technology ofcontrolling the pre-hydrolysis process in the production of thecatalytic cellulignin fuel.

6—Table 4a illustrates the physical characteristics of the Micropores(Active Sites) and table 4b presents the distribution of the Meso andMacropores. The former was determined by BET—Adsorption of N2 and thelatter was determined by Hg porosimetry. The total specific areameasured by BET is about 2.20 m²/g, and the specific area of the macroand meso pores were the larger portion of the total area. Thecalculation thereof from the average radius of the pore measured by Hgporosimetry results in 1.80 m²/g, admitting a cylindrical symmetry ofthe pore (I=2r). This conclusion is coherent with the low microporesvolume (1.1×10⁻³ cm³/g) measured by BET. The distribution of the macroand meso pores has its maximum value ranging from 1 to 5 μm (1000-5000nm), this size coinciding with the voids of the of the cellsphotographed by MEV (FIGS. 3 a, 3 b, and 3 e). The data of table 4 andthe microstructures of MEV permit the complete characterization of thecatalytic cellulignin fuel according to the present invention. Themicropores are measured by the iodine number equal to 100; in the caseof the catalytic cellulignin still there is no instrumentation thatenables one to appraise the of the micropores (2 nm) contribution in thecombustion.

TABLE 4a Physical characterization of the Micropores (Active Sites - φ <2.0 nm) Micropore Crystalline Specific Micropore volume⁽²⁾ density⁽¹⁾area⁽²⁾ Radius⁽²⁾ (×10⁻³ Samples (g/cm³) (m²/g) (nm) cm3/g) 1 - Wood1.284 0.459 0.948 0.217 2 - Cellulignin without grinding -pre-hydrolysis time 2a - 0.5 h (oscilation) 1.331 0.756 0.980 0.371 2b -1.0 h (oscilation) 1.337 1.463 0.905 0.662 2c - 1.0 h (static) 1.3341.342 0.970 0.651 2d - 2.0 h (oscilation) 1.351 2.249 0.964 1.080 3 -Griding effect 3a - cellulignin without 1.252 2.483 1.197 1.496 grinding3b - 297 μm < φ < 354 μm 1.353 2.758 0.997 1.375 3c - 177 μm < φ < 210μm 1.368 2.013 1.135 1.143 3d - 125 μm < φ < 149 μm 1.375 2.114 1.0321.090 3e - 88 μm < φ < 105 μm 1.372 1.915 0.962 0.921 3f - φ < 74 μm1.346 3.179 0.914 1.454 4 - Wood and carbonized Cellulignin 4a -carbonized wood 1.314 0.965 1.024 0.494 4b - cellulignin de 0.5 h 1.2922.474 1.014 1.254 4c - cellulignin de 1.0 h 1.327 1.452 1.002 0.727 4d -cellulignin de 2.0 h 1.371 1.932 1.009 0.974 4e - double carbonization1.421 2.497 1.000 1.248 ⁽¹⁾Picnometry of Helium; Equip. used:Ultrapicnometer - Model: 1000 from Quantachrome - Version: 1.62 ⁽²⁾BET -Adsorption of N2; Equip. used: Adsorptometer - Model: Nova fromQuantachrome - Version 3.70

TABLE 4b Distribution of Meso (2 nm < 0 < 50 nm) and Macro (0 > 50 nm)pores (cm³/g) Cylindrical Geometri of the Porosimetry of Mercury Pore (r= 21) D_(P-) Pore Diameter (nm) (S/V) = (2πr² + xrl)/(πr²l) Average 10³× D_(p) < 2 × 10³ < (S/V) = (2/r) Samples radius (nm) D_(P) < 10 10 <D_(P) < 100 100 < D_(P) < 1000 2 × 10³ D_(P) < 5 × 10³ Total S = 2 V/rM³/g) 3a-cellulignin without  631.2 0.018 0.076 0.233 0.038 0.056 0.4212.668 grinding 1025.2 0.004 0.022 0.084 0.039 0.048 0.197 0.768 0 > 2 mm0 > 354 μm 3b-287 μm < 0 < 354 μm  893.0 0.006 0.033 0.095 0.052 0.0460.232 2.080 210 μm < 0 < 250 μm  987.2 0.009 0.027 0.084 0.048 0.0510.219 1.755 3c-177 μm < 0 < 210 μm — — — — — — — — 149 μm < 0 < 177 μm 845.8 0.003 0.018 0.094 0.082 0.035 0.212 2.004 3d-125 μm < 0 < 149 μm— — — — — — — — 105 μm < 0 < 125 μm 1180.6 0.007 0.025 0.090 0.058 0.0490.229 1.553 3e-88 μm < 0 < 105 μm — — — — — — — — 74 μm < 0 < 88 μm1003.2 0.009 0.025 0.091 0.051 0.042 0.218 1739 3e- — 0.008 0.023 0.1080.163 0.530 0.830 3.676 0 < 74 μm 1715.4 S = Surface of the pore V =Volume of the pore r = Radius of the pore l = Length of the pore

7—The major application of the cellulignin of the present invention isas a fuel for boilers, gas turbine and for the generation of energy bymagnet hydrodynamics (MHD). However, apart from the uses as a fuel,there are several other applications in the following areas: a volumecomponent for animals food, pyrolysis for the production of oils andactivated coal, production of carbon black (incomplete combustion),production of methanol, cellulignin resinates (agglomerates, MDF—MediumDensity Fiber), substrate for semisolid fermentation (fungi, bacteriaand enzymes), etc.

Even though the precise chemical formula of the cellulignin according tothe invention may vary. its empirical chemical formula is presented inTable 5, in comparison with the empirical formulas of wood, biomasscomponents, mineral coal and fuel oils, these data providing a goodreference for the understanding of the improved effects achieved by thefuel developed now.

TABLE 5 Chemical formulas of the several fuels Empirical Fuel MaterialCarbon Ashes formula (moisture) Volatile (%) fixed (%) (%)approximate 1. Soft wood (46%): Douglas fir 86.2 13.7  0.1C_(4.4)H_(6.3)O_(2.5)N_(tr) Pitch pine — — — C_(4.9)H_(7.2)O_(2.0)N_(tr)Hemlock 84.8 15.0  0.2 C_(4.2)H_(6.4)O_(2.8)N_(tr) 2. Hard wood (32%):Poplar — — — C_(4.3)H_(6.3)O_(2.6)N_(tr) White ash — — —C_(4.1)H_(7.0)O_(2.7)N_(tr) 3. Barks: Oak — — —C_(3.3)H_(5.4)O_(3.1)N_(tr) Pine — — — C_(4.5)H_(5.6)O_(2.4)N_(tr) 4.Wood Dry (17%) — — — C_(4.4)H_(5.0) O_(2.4)N_(0.02)(H₂O)_(1.1) Humid(50%) — — — C_(4.4)H_(5.0) O_(2.4)N_(0.002)(H₂O)_(5.6) 5. Compo- nentsof biomass: Cellulose (C₆H₁₀O₅)_(n) Hemicellulose (C₅H₁₀O₅)_(n) Lignin(C₁₀H₇O₄)_(n) Catalytic C_(5.5)H_(4.2)O_(1.8)N_(tr) celluligninCellulose coal C_(6.7)H_(3.3)O_(1.0)N_(tr) 6. Tar:C_(4.7)H_(5.8)O_(3.0)N_(tr) 7. Mineral coals: Lignite (37%) — — — Sub-bitumenous A(14%) — — — — B(25%) 40.7 54.4  4.9C_(8.0)H_(4.8)O_(1.0)N_(tr) C(31%) — — — — Bitumenous Low volatile 17.771.9 10.4 C_(6.7)H_(4.3)O_(0.14)N_(0.11) Medium — — — — volatile Highvolatile  6.4 81.4 12.2 C_(6.8)H_(2.3)O_(0.12)N_(0.09) Antracitic  6.481.4 12.2 C_(6.8)H_(2.3)O_(0.12)N_(0.06) 8. Oils — — —C_(7.3)H_(11.1)O_(0.09)N_(0.02) (APF - A1)

As can be seen, biomasses have low carbon contents (4.3 moles performula-gram), middle hydrogen contents (6.5 moles per formula-gram),and high oxygen contents (6.5 moles per formula-gram). Mineral coalshave high carbon contents (6.5 moles per formula-gram), low hydrogencontents (4.3 moles per formula-gram), and low oxygen contents (0.15moles per formula-gram). The catalytic cellulignin according to theinvention is in an intermediate position with carbon (5.5) and hydrogen(4.2) contents tending to mineral coal, but with intermediate oxygencontents (1.8 moles per formula-gram). In fact, the catalyticcellulignin comes close to lignite coal being obtained, however, in 20minutes of pre-hydrolysis, while lignite coal took millions of years tobe formed.

Another great advantage of the cellulignin fuel developed now is itsvery tow ashes contents, thus meeting, for instance, the requirements ofclean fuel for gas turbine (Na+<5 ppm) when processed in pre-hydrolysiswith deionized water. This is due to the pre-hydrolysis processefficiency that solubilizes K in the form of water-soluble K₂SO₄, whichis later leached in the washing step. All impurities contained in thewood are reduced and even those of higher contents, such as Ca, Mg, al,and Si present in eucalyptus wood, for example, do not cause hotcorrosion on the superalloys of the gas turbines. The cycloning of thecombustion gases from the fuel of the invention proved to be highlyefficient in reducing the ashes contents at the level required for gasturbines (total particulate <200 ppm and particulate with a diameter >5μm being in a proportion lower than 8 ppm).

A few points should also be stressed with respect to the improvedcharacteristics of the cellulignin fuel of the present invention, whichbring expressive advantages for combustion processes, when compared toconventional fuels.

As already mentioned before, in the solid pyrlysis zone in a combustionprocess, high temperatures favor the production of volatile compounds,and low temperatures favor the production of coal. As already indicatedby table 2 above, the products resulting from the cellulose and xylanpyrolysis result in high tar contents, which causes a secondarycombustion close to the oils for wood. However, there is no xylan in thecatalytic cellullignin according to the present invention, which leadsto lower coal contents in this zone. It is further pointed out that theglobulization of lignin in the production process of catalyticcellulignin fuel of the invention favors the formation of volatiles anddecreases the coal contents. In addition, and considering the influenceof moisture on the particle pyrolysis, it follows that the catalyticcellulignin fuel maximizes the combustion temperature, increases thevolatile contents and decreases the formation of coal contents sinceprovides the possibility of a burning without moisture and with lowashes contents.

Other technical advantages obtained according to the invention may beclearly observed during the pre-combustion reactions and in the primarycombustion reactions, as well as in the post-combustion reactions of thecellulignin fuel.

In the pre-combustion step, it is observed that, in the case of thecatalytic cellulignin, there is a decrease in the ash contents, thewater contents and xylans are non-existent, and these aspects favorCH₄formation (a product from the decomposition of R″-cellulose) insteadof C₂H₆ (product from the decomposition of hemicellulose, non-existentin cellulignin). During the primary combustion, the combustion ofcellulignin takes place at higher temperatures, like the combustion ofCH₄ resulting from the decarboxilation of the acetic acid anddecarbonilation of the acetaldehyde resulting from the opening of therings. This explains why, in practice, the catalytic cellulignin has acombustion similar to that of natural gas and of volatile liquid fuels.Finally, during the post-combustion step the ratio C:H is of 1:0.76 forthe case of the catalytic cellulignin, that is to say, it is closer tothe mineral coals than to wood. The average oxygen contents, however,favor the formation of CH₄, CO₂ and CO, reinforcing the explanation forthe high reactivity of the catalytic cellulignin.

In order to enable a better understanding of the similarity of thefeatures of combustion of the catalytic cellulignin of the presentinvention as compared with those of the mineral coal, a modern theory ofthe combustion of porous particles (Essenhigh) is given below in view ofits significance for the invention of the combustion of cellulignin.

The mass loss rate: m=m(a,σ) wherein m=mass of the spherical particle,a=particle radius, d=2a=particle diameter, σ=particle density andm=(4/3)πa³σ.$\frac{\mathbb{d}m}{\mathbb{d}t} = {{\frac{\partial m}{\partial a}\frac{\mathbb{d}a}{\mathbb{d}t}} + {\frac{\partial m}{\partial\sigma}\frac{\mathbb{d}\sigma}{\mathbb{d}t}}}$$\frac{\mathbb{d}m}{\mathbb{d}t} = {{4\pi\quad a^{2}\sigma\frac{\mathbb{d}a}{\mathbb{d}t}} + {\frac{4}{3}\pi\quad a^{3}\frac{\mathbb{d}\sigma}{\mathbb{d}t}}}$$R_{s} = {\frac{{\mathbb{d}m}/{\mathbb{d}t}}{4\pi\quad a^{2}} = {{{\sigma\frac{\mathbb{d}a}{\mathbb{d}t}} + {\frac{a}{3}\frac{\mathbb{d}\sigma}{\mathbb{d}t}}} = {{R_{s} + R_{i}} = {{{R_{s}\left\lbrack {1 + \frac{R_{i}}{R_{s}}} \right\rbrack}\frac{R_{i}}{R_{s}}} = {{\frac{a}{3\quad\sigma}\frac{\mathbb{d}\sigma}{\mathbb{d}a}} = {\frac{1}{3}\frac{\mathbb{d}\left( {\ln\quad\sigma} \right)}{\mathbb{d}\left( {\ln\quad a} \right)}}}}}}}$

R_(s)=mass loss rate by the external surface of the particle (g/cm²s) eR_(i) is the mass loss rate by the internal surface. The above equationis an inexact differential equation impossible of being integrated dueto the lack of a relationship between σ and the a (integration way).

Essenhigh (1988) proposed the utilization of the equation of Thiele(1939) of catalysis as a way of integration of R_(s)$\frac{\sigma}{\sigma_{0}} = {\left( \frac{d}{d_{0}} \right)^{\alpha} = {{\left( \frac{a}{a_{0}} \right)^{\alpha}\therefore a} = \frac{\mathbb{d}\left( {\ln\quad\sigma} \right)}{\mathbb{d}\left( {\ln\quad a} \right)}}}$

wherein α=0 stands for density, σ constant with combustion by theexternal surface and α→∞ stands for constant diameter with combustionover the internal surface (This concept is similar to the catalysis overthe external surface or over the internal surface).

Calculating the R_(r)/R_(e) relationship it follows that:$\frac{R_{i}}{R_{s}} = {{\frac{R_{i}}{R_{m}}\frac{R_{i\quad m}}{R_{s}}} = {\eta\quad\frac{R_{i\quad m}}{R_{s}}}}$

wherein R_(tm) is the maximum rate of internal loss and η=R_(r)/R_(tm)is the Thiele effectiveness factor (0<η<1) representing the relationshipbetween the real internal loss and the maximum possible internal loss(For large particles or particles of low porosity, the internal massloss is negligible and η→0 while for small particles and high densitythe internal loss of mass is maximum and η=1).

Defining S_(v) as the internal surface area per volume unit V_(p)((cm²/cm³)=1/cm) and S_(p) as the external surface area of the particle,it follows that the relationship R_(tm)/R_(e) is proportional to therelation of the internal and external areas in:$\frac{R_{i\quad m}}{R_{s}} = {\frac{V_{p}S_{v}}{S_{p}} = {\frac{\frac{4}{3}\pi\quad a^{3}S_{v}}{4\quad\pi\quad a^{2}} = \frac{a\quad S_{v}}{3}}}$$\frac{R_{i}}{R_{s}} = {{\frac{a}{3}S_{v}\eta} = {{\frac{1}{3}\frac{\mathbb{d}\left( {\ln\quad\sigma} \right)}{\mathbb{d}\left( {\ln\quad a} \right)}} = \frac{\alpha}{3}}}$α = a  S_(v)η

For mineral coals, α ranges from zero to 3, exceptionally reaching thevalue of 6. For the catalytic cellulignin fuel, we have S_(v)=σS_(g)wherein S_(g) is the internal surface per unit of mass, the followingvalues resulting for a particle of 200 μm:

S_(g) m²/g 0.01 0.1 0.2 0.3 0.4 0.5 1.0 10.0 m²/kg 10 10² 2 × 10² 3 ×10² 4 × 10² 5 × 10² 10³ 10⁴ α = aσS_(g)η 1 10 20 30 40 50 100 1000(σ/σ₀) = (d/d₀)_(α) 0.9 0.349 0.122 0.042 0.015 0.005 2.7 × 1.7 ×p/(d/d₀) = 0.9 10⁻⁵ 10⁻⁴⁸

This means that for a specific surface larger than 0.4 m2/g (α=40), thecatalytic cellulignin fuel burns mainly from the internal surface,maintaining the particle diameter approximately constant and varying itsdensity (burning of a fractal−1^(a) zone), characterizing the newinvention as a large-scale, completely catalytic, fuel obtained from thepre-hydrolysis of biomass available in nature. Tests of specific surface(BET, porosimetry of mercury and MEV) indicate an average value of 2.0m2/g, resulting in a α=200. The particles of liquid fuel bum from theexternal surface (α=0-3^(a) zone), and the particles of mineral coalhave partial internal combustion (0=or <α=or <3−2^(a) zone).

For the case of mineral coal, α=Sv/γ, wherein γ is the Thyele parametergiven by:λ=(S _(v) {overscore (κ)}/ρD _(e))^(1/2); α=(ρD _(e) S _(v)/{overscore(κ)})^(1/2)

wherein k=constant of the reaction rate, ρ=reactive gas density andDe=coefficient of internal diffusion. For the catalytic celluligninthere is no need for independent determination of these parameters,because they combine, resulting in a relatively high value of α(α=or>100).

In the catalytic combustion, the oxygen does the direct attack on thecarbon atom as a two-stage reaction (adsorpotion-desorption),illustrated in FIG. 5. Oxygen is adsorbed and desorbed, forming CO₂ orCO, which is then deadsorbed.

The components and products of the reaction are C, O₂, CO₂, H₂O, H₂, andCO, according ${{2C_{f}} + O_{2}}\overset{k_{1}}{\rightarrow}{2{C(O)}}$${C_{f} + {CO}_{2}}\underset{\overset{\quad}{\underset{k_{2}}{\leftarrow}}}{\overset{k_{1}}{\rightarrow}}{{C(O)} + {CO}}$${C_{f} + {H_{2}O}}\underset{\overset{\quad}{\underset{- k_{3}}{\leftarrow}}}{\overset{k_{3}}{\rightarrow}}{{C(O)} + H_{2}}$${{2C_{f}} + H_{2}}\underset{\overset{\quad}{\underset{- k_{4}}{\leftarrow}}}{\overset{k_{4}}{\rightarrow}}{2{C(H)}}$${C(O)}\overset{k_{5}}{\rightarrow}{{CO} + C_{f}}$${2{C(O)}}\overset{k_{5}}{\rightarrow}{{CO}_{2} + C_{f}}$to the following reactions:

wherein Cf indicates a free site, C(O) stands for a chemically adsorbedoxygen atom and ki are reaction constants. The volatiles (CO, H₂)produced by the catalytic combustion complete their combustion outsidethe particle with a very short combustion time (3 ms). The determinedcombustion time is that of the adsorption-deadsorption process, beingequal to or shorter than 20 ms (0.02 s) for the catalytic cellulignin.

The burning time for mineral coal, liquids (oils) and for catalyticcellulignin fuel measured in the form of isolated particle and in theform of powder cloud is illustrated in FIG. 6 and the formulas utilizedin the corresponding calculations are presented below.

Attachment I: Combustion Times

1a—Coal Cumbustion

Burning Time

i) at constant density:$t_{b} = {\frac{\rho_{0}{RT}_{m}}{96\phi\quad{Dp}_{g}}d_{0}^{2}}$

ii) at constant diameter$t_{b} = {\frac{\rho_{0}{RT}_{m}}{144\quad\phi\quad{Dp}_{g}}d_{0}^{2}}$wherein:

-   -   ρ₀=initial density of the particle≅1000 kg/m³    -   R=universal constant of the gases=0.8106 m3 atm/(kmolK)    -   T_(m)=average temperature=1600 K    -   D=diffusion coefficient=3.49×10⁻⁴ m²/s    -   P_(g)=partial oxygen pressure=0.2 atm    -   φ=order of reaction=2    -   d₀=initial particle diameter (m)        1b—Combustion of Liquids        Burning Time $t_{b} = \frac{d_{0}^{2}}{\lambda}$        wherein:    -   d₀=initial diameter    -   λ=evaporation rate=10±2)×10⁻³ cm²/s for hydrocarbons burning in        air.

In the first form, the burning time is shorter than that of mineral coalbecause it is a much more reactive fuel. In the form of a powder“cloud”, there is a decrease in the thermal losses due to the energytransmission by radiation among the particles, decreasing the burningtime for values similar to those of the volatile liquids. One way ofanalyzing this question is by means of the Krishna and Berlad's energybalance for ignition of powder cloud of mineral coal.${({const})T_{i}^{\beta - 1}} = \frac{\lambda_{0}/a}{1 + {R^{2}{D/a^{2}}\sigma}}$

wherein the first term is the energy generation rate, a is the radius ofthe particle, R is the radius of the cloud, ρ is the particle density, Dis the density of the cloud, λ₀ is the air thermal conductivity and β isan empirical coefficient. If R²D/a²σ<<1 it follows that a T_(t) _(β)⁻¹=(const.) and if R²D/a²σ>>1, then T_(i) _(β) ⁻¹=(const)a. The latteris in accordance with the world experience that recommends grinding themineral coal at temperatures not higher than 70° C. to avoidincineration of the powder cloud in the mills. For catalytic celluligninfuel injection, we have R=0.1 m. a=100×10⁻⁶ m, σ=500 kg/m³. D=0.4 kg/m³resulting in R²D/a²σ=800>>1. The smaller the particle size, the lowerthe ignition temperature of the powder cloud. For mineral coal, thetheoretical ignition temperature of the cloud is 300 at 500° C. and forcatalytic cellulignin, the ignition temperature is on the order of 350°C. (pyrolysis temperature). The presence of oxygen in the molecule ofthe catalytic cellulignin fuel favors the similarity of its combustionprocess to that of mineral coal (however, with higher reactivity andhigher ignition temperature) with respect to the combustion of wood,which is of five steps and seriously limited by the presence of water.

In order to establish the combustion characteristics, catalyticcellulignin particles of different diameters were burned by means ofLASER ray ignition and determination of irradiation intensity withphotodiodes. The results are shown in FIGS. 7 a and 7 b, where one cansee two regimes, namely: 1) above 250 μm the combustion is of theconventional type (limited by the transport of mass inwards and outsidethe particle) and 2) below 251° μm the combustion is not limited by massflow (process of adsorption of O₂—deadsorption of CO). The two regimesadjust to Thiele's catalytic combustion. Attention is drawn to theimportance of maintaining the crystalline characteristic of thecellulose in the prehydrolysis process to render the grinding ofcellulignin particles smaller than 250 μm inexpensive.

a) Conventional combustion (φ>250 μm): the catalytic cellulignin isdried outside the combustion equipment and the drying zone isnon-existent. The heating is rapid, the generation of volatiles ismaximized while coal generation is minimized. The catalytic cellulignindoes not contain xilan, its solid pyrolysis predominating, that is tosay, opening of the ring with production of acetic acid, acetaldehydeand coal by decarbonilation of the acetic acid and decarboxylation ofthe acetaldehyde in the formation of CH₄, CO₂ and CO. The zones ofvolatiles primary and secondary combustion are the same as describedbefore.

b) Catalytic combustion (φ<250 μm): The pre-hydrolysis displaces thebiomass in the direction of the combustion of mineral coal. The maincharacteristic is that combustion is no more limited by the mechanism ofthe oxygen transport into the catalytic cellulignin and of CO therefromdue to the particle microstructure. In this way, there is physical (O₂)and chemical (O) adsorption in active sites and Boudouard's reaction isfavored. Reactions of hydroxylic groups cause rapid reactions in theheating and solid pyrolysis zones. The catalytic combustion occurs inthe average internal surface (2.0 m²/g), the contribution of theexternal surface (0.1 m²/g) of the particle being secondary. Theframework of the catalytic cellulignin is that of a fractal that burnswhile maintaining the diameter of the particle approximately constantand decreasing the particle density. When the wall of the fractalthickness reaches a critical size, a collapse of the particle(sublimation) takes place. Therefore, the process eliminates theformation of residual coal, resulting in complete combustion.

The combustion equipment usable for the catalytic cellulignin of thepresent invention will depend upon the type of specific combustion to beemployed. In this regard, the main methods of biomass combustion are:combustion in pile, thrower-spreader, suspension, and fluidized bed, thethrower-spreader combustor is the most prominent from the industrialpoint of view. The characteristic of the first two is the completephysical separation of the five combustion zones. In the combustion bysuspension of dry biomass particle (φ<2 mm, TU <15%), all “zones” takeplace in the middle of the air, in a sequential way. The suspensionburning is the closest to the burning of liquid fuels. This is the caseof the cellulignin proposed now, which comes close to the combustion ofgases and liquids due to its catalytic combustion.

The combustion in fluidized bed maintains the fuel in a bed with sand orlime suspended by air. All the reaction zones take place in the sameplace (not separable physically). The combustion efficiency is low dueto the excess air (100-140%) necessary to maintain the fluidized bed,and the temperature is kept below the ashes melting point in order notto cause the bed to collapse. In the case of the catalytic celluligninof the invention, the suspension combustion may be carried out withstoichiometric air and without limitation of temperature, since it has avery low ash content. The three main parameters in the combustion areuseful heat, thermal efficiency and combustion temperature.Hv=CCS−PT; η=[1−(PT/CCS)]×100

wherein CCS is the upper calorific capacity and PT are the thermalchimney losses, ashes (including not-burnt carbon), radiation andothers. The chimney losses are given by:${PT} = {{\sum\limits_{i = 1}^{n}{m_{1}\left( {{Cp}_{1}\Delta\quad T} \right)}} + {m_{H_{2}O}\lambda_{H_{2}O}}}$

wherein mi is the moles of the chimney gases (CO₂, O₂, N₂, H₂O), Cpi isthe calorific capacity of each species, ΔT is the difference intemperature between the chimney and the environment m_(H2O) is thenumber of moles of water and λ_(H2O) is the molar water vaporizationvalue.

The losses by radiation are of about 4% and other losses (ash, not-burntcarbon) are about 2%. The combustion efficiency of a wood with 50%moisture is 68%; with 17% moisture, it is 79%, and that of the catalyticcellulignin is 85% (close to the values of the mineral coal) due to theabsence of moisture, ash and excess air. The catalytic cellulignin fuelof the invention permits the achievement of temperatures close to theadiabatic one (1920 K), although the temperatures of thevapor-generating tubes of the boilers are limited to 840 K.

The heat release rates for the different combustion methods are given byI=h dW/dt, wherein I is the flame intensity, dW/dt is the change inweight in function of the time, and h is the combustion heat. Table 6shows several rates for the different combustion methods:

TABLE 6 Heat release rates for different combustion methods. Combustionmethod Wood Mineral coal Combustion in pile 8.5 GJ/m²h Inclined grid 3.5GJ/m²h Thrower-spreader 10.4 GJ/m²h 8.8 GJ/m²h Suspension 550 GJ/m³hFluid bed 470 GJ/m³h

The reactivity of the catalytic cellulignin is slightly higher than thatof biomass (absence of water, larger specific surface) and thecombustion heat is the double, leading to a heat release rate twice ashigh as that of wood. For example, 9 kg/h of catalytic cellulignin withcombustion heat of 20 MJ/jg burn in suspension in a volume of φ=2 cm andL=50 cm, that is, (9×20/(π×(0.01)²×0.5)=1.146 GJ/m³h.

The examples of equipment given below will better illustrate the presentinvention in a better way. However, the data and procedures illustratedmerely refer to a few embodiments of the present invention and shouldnot be taken as being limitative of the scope of the invention.

The complete characterization of the catalytic cellulignin fuel involveselements of the cellulignin as starting material, of the combustionspecific characteristics and of the fuel handling and controllingequipments.

FIG. 8 illustrates a feeding system composed of a cellulignin tank(8.1), a rotary valve or helical feeder for dosing the cellulignin feed(8.5 and FIGS. 9 and 10), feeding line of the air/cellulignin two-phasefluid (rate 3.28:1 by weight) (8.6) and applications in boilers andovens (pressure close to the atmospheric one, T=1900° C.), in gasturbines (pressure of 7-14 atm, T=600-1100° C.). The cellulignin tankmay be either stationary (preferably in vertical cylindrical form), ormoveable (installed in carriage similar to the tanks for carrying animalfood or cement). Due to the tendency of cellulignin to settle, the tanksare preferably provided with a conic or plane bottom and with powderhandlers of the rotary-shovel type (8.2, 8.3, 8.4), helical feeders or abottom with moveable compressed-air lining. At the exit of the rotaryvalve or helical feeder for dosing the cellulignin, drag air is injectedfor two-phase flow at the ratio of 3.28:1. The two-phase flow may bemade of metallic, plastic pipes or hoses, the air/cellulignin mixturebehaving as if it were a gas or a liquid. Under low pressure. theenergetic density of the air/cellulignin mixture is of 7.14 MJ/m3, whilethat of natural gas is 32.9 MJ/m3 and that of the fuel oils is 28.0MJ/m3, permitting still compact, simple installations and significantlengths of the piping, in order to meet the layouts of the factories,thermoelectric power stations, etc.

The helical feeder shown in FIG. 9 is composed of a body (9.1), bushing(9.2), helical feeder (9.3), powder retainer (9.4), bearings (9.5),flanges (9.6). driving pulley (9.7) and air injection for two-phase flow(9.8). The dosage of cellulignin is carried out by turning the helicalfeeder and varying its diameter and, in general, it is utilized for lowcapacities (<150 kg/h). The elimination of the influence of pressuredifference between the cellulignin tank and the drag gas in dosing thepowder carried by the helical feeder is carried out by means of theimpedance of the length of the helical feeder between the tank body andthe drag air of the two-phase flow. The rotary valves illustrated inFIG. 10 are available on the market for capacities higher than 150 kg/hand comprise a body (10.1), shovels (10.2), driving shaft (10.3),inspection window (10.4) and possibly cooling (10.5). The dosage is madeby means of rotation, the diameter and the length of the valves.

Combustors

The direct use of combustors in boilers and ovens is possible because ofthe low content of the cellulignin ashes (<0.2%) and the resourcesalready existing in this equipment for removing residual ashes. Forapplications in gas turbines, the following measures are necessary: a)combustion chamber with injection of primary air (stoichiometriccombustion) and secondary air (drag of the ashes from the combustionchamber to the cyclone and cooling of the combustion gases down to theworking temperature of the turbine); b) gas-cleaning cyclone (removal ofthe particulate); and c) possible ceramic filter for high temperatureturbines (1100° C.—monocrystalline superalloys), and these filters areindispensable to polycrystalline superalloys or with directionalsolidification. The specifications of Na+K<5 ppm, in the catalyticcellulignin fuel with total particulate contents of 200 ppm, withdiameter >5 μm lesser than 8 ppm in the combustion gases, have beenachieved without the need for ceramic filters.

Axial Combustor

FIG. 11 shows an example of an axial combustor to characterize thecombustion of the catalytic cellulignin. The ignition may be carried outin several ways, such as by microblowtorches of GLP, natural gas, etc.,electric arc, electric resistance or hot gas tube. The fact that it iseasy, automation and low cost favor the ignition with blowtorches ofGLP, natural gas (consumption of 0.022 kg of GLP/kg of cellulignin,representing 5% of the calorific capacity of the combustor). Two factorsrelated to catalytic cellulignin ignition are pointed out: first, theneed for it to be heated up to the pyrolysis temperature (350° C.);second, the operational security of the catalytic cellulignin withrespect to the combustible gases and liquids that ignites at roomtemperature. The practical applications may be made with any type ofcombustor (axial, swirler, cyclonic, etc.)

The axial combustor is composed of a mounting plate (11.1) with orwithout cooling, cellulignin injector (11.2),stoichimetric-combustion-air injector (11.3), fixture of the ignitionblowtorches (11.4) with or without cooling, ignition blowtorch of GLP,natural gas, etc. (11.5), window with view-finder (11.6). Ignitionblowtorches are as small as available on the market, because thecatalytic characteristics of cellulignin enable their instantaneousignition and propagation for the two-phase air/cellulignin flow. Thepower of the ignition blowtorch is on the order of 5% of the power forlow capacity (50 kW) combustors and tends to negligible percentages forhigh capacity combustors. For the two-phase flow with velocity of 8.5m/s and a diameter φ=16.5 mm, the ignition spreads at a length of 100mm, giving an ignition time of 0.012 s=12 ms. The combustion is completeat a length of 0.7 m, giving a residence time of 1/(8.5/2)=0.16 s=160 ms(one has utilized the average velocity of 8.5/2=4.25 m/s, since theinjection velocity in the beginning of the flame is of 8.5 m/s and thevelocity at the end of the flame is virtually nil). Theresistance-time/ignition-time relationship is on the order of ten times.The ignition times of the catalytic cellulignin tend to the ignitiontimes of gases, which are on the order of 3 ms.

In general, mineral coal and liquid fuels generate a very long flamelength, due to the longer burning times (see FIG. 6). thus requiringcombustors of the axial-swirler type for reducing the flame length. Thecatalytic characteristic of cellulignin allows one to use axialcombustors with relatively short flame lengths. The extinguishing of theignition blowtorch results in extinguishing the flame of the catalyticcellulignin, due to the need for it to be pyroliyzed at 35° C.,imparting to the catalytic cellulignin complete security in its handling(non-incendiary and non-explosive fuel) The catalytic cellulignin doesnot contain hemicellulose, which is responsible for the incendiarycharacteristic of biomasses in the form of straws (pyrolysistemperature=200° C.), as well as it does not pyrolyze at lowtemperature, and so does not have the incendiary characteristics of thegases and liquid fuels (low flash point). On the other hand, above 350°C., its combustion is catalytic with ignition times close to that ofgases.

Gas Turbines

For applications of cellulignin combustors in gas turbines, twoadditional steps are required, namely: cooling of the gases and acyclone for reducing particulates. FIGS. 12 a and 12 b show thecellulignin combustor, cycloning and particulate collector withhorizontal or vertical assembly. It is composed of combustor (12.1),combustion chamber (12.2), inlet of cooling air (12.3), chamber ofcooling air (12.4), homogenization sector (12.5), cyclone (12.6),particulate collector (12.7), and duct of connection with the turbine(12.8). In the vertical position, an ash collector (12.9) is addedbefore the combustion gases are directed to the cyclone for collectionof the molten ashes during the stoichiometric combustion.

The combustor illustrated is manufactured from stainless steel, exceptfor the combustion chamber, which is made from superalloys due to thehigh temperatures (1920° K), being cooled by the cooling air. A portionof the cooling air penetrates the bores in the wall of the combustionchamber, creating a peripheral layer of drag air for dragging the moltenashes and particulates.

One of the main characteristics of the gas turbines is their versatilitywith regard to fuels, operating with gases such as natural gas,evaporated oils and process gases (refineries, blast-furnaces andgasifiers); liquids such as clean liquids that are volatile Naphthas,light distillates (Diesel, kerosene) and viscous and heavy residualoils; and solids. Liquid fuels with high ash contents (crude andresidual oils) require cleaning equipment prior to their utilization.

Table 7 illustrates the properties of the three types of conventionalfuels and of the catalytic cellulignin. The latter is placed between thenatural gas and light distillates (clean fuels) and the mixtures ofheavy distillates and low-ash crude oil. It does not contain V₂O₅, WO₃,MO₃, or Pb, and the S content is very low. The Na+K for the cleancatalytic cellulignin concentration is close to that of the clean fuelswhile for normal catalytic cellulignin it is dose to that of heavyresidual high-ash crude oils (table 8). The prehydrolysis carried outwith deionized water is an effective technology of producing the cleancatalytic cellulignin as a fuel for gas turbines. The only parameter outthe conditions of clean fuel is the total ash contents (<0.1%). Theseare, however, significantly reduced in the cyclone, reaching totalparticulate contents <200 ppm, and contents lower than 8 ppm forparticles with size bigger than 5 μm.

Natural gas distillates do not need a fuel treatment. Mixtures of heavydistillates, low-ash crude oils and especially heavy residual high-ashcrudes need washing of the fuel that is based on the water-solubility ofsodium, potassium, and calcium. There are four conventional washingprocesses, namely: centrifuge, D.C. electric, A.C. electric, and hybrid.The catalytic cellulignin dispenses with any washing process that hasbeen used for reducing the Na+K contents from 100 ppm down to levels offrom 5 to 0.5 ppm in crude and residual oils.

TABLE 7 Properties of the Fuels Mixtures if Distillates a Low Ash CrudesDistillates and Naphtha Catalytic Cellu- Typical Heavy High Ash CrudeKero- lignin Low Ash Crude from Distil- and Heavy Properties sene #2 Oil#2 JP-4 Clean Normal crude Libia lates Residues Flash Point (° C.) 54/7148/104 66/93 <T.A. (1) 350 (2) 350 (2) 10/93 — 92 79/129 Flow Point (°C.) −45 −48/−12 −23/−1 — Any (3) Any (3) −9/43 20 — −9/35 Visc. CS to38° C. 1.4/2.2 2.48 2.0/4.0 0.79 (4) (4) 2/100 7.3 6.20 100/1800 2.67SSU — 34.4 — — — — — — — — Grau API — 38.1 35.0 53.2 — — — — — — SecofDesn. at 38° C. 0.78/ 0.85 0.82/0.88 0.7545 0.50 0.50 0.80/0.92 0.840.8786 0.92/1.05 0.83 (5) Calorific Power MJ/kg 44.6/ 42.3 43.9/45.320.0 20.0 43.9/44.8 42.2 42.1 42.3/43.7 45.5 Ashes 1 a 5 0.001 0 a 20 —1000 2000 20 a 200 36 — 100/1000 Coal Residues 0.01/01 0.104 0.03/0.3 —0.3/3 2/10 — — Sulfur (%) 0.01/0.1 0.164 a 0.1/0.8 0.047 <80 ppm 2800.1/2.7 0.15 1.075 0.5/0.4 0.293 ppm Hydrogen 12.8/ 12.83 12.0/13.214.75 4.3 4.3 12.0/13.2 — 12.40 10.0/12.5 14.5 Na + K (ppm) 0/1.5 —0/1.0 — 5 <60 0/50 2.2/4.5 — 1/350 Vanadium 0/0.1 — 0/0.1 — Zero Zero0/15 0/1.0 — 5/400 Lead 0/0.5 — 0/1.0 — Zero Zero — — — 0/25.0 Calcium0/1.0 0/2.0 0/2.0 — <500 500 — — — 0/50 Distillates and Mixtures ofDistillates and High Ash Crude and Heavy Resi- Properties NaphthaCatalytic Cellulignin Low Pressure Crude dues Preheating of the No NoYes Yes fuel Atomization Mechanics/Low No Low Pressure/High Pres- HighPressure Air Pressure Air sure Air Disalination No No Some Yes InhibitorNo No (Limited) Limited Always Washing of the Tur- No No Yes (except fordistillate) Yes bine Initial Fuel With Naphtha Ignition (GLP, naturalSome Fuels Always gas, heated tubes, elec- tric resistance) Cost HigherIntermediate Intermediate Lower Description Low-quality DistillatePorous powder with Low Ash, Limited Level of High Ash Low Volatilityfree of ashes limited ash contents, Contaminants that can be reduced bycyclones Designation ASTM 1GT, 2GT, 3GT (3-GT) 3GT 4GT Turbine InletTem- Higher Intermediate Intermediate Low perature

TABLE 8 Inorganic impurities (mg/g) of Eucalyptus, Catalytic Celluligninand Pre- hydrolysate Ca K Na Mg P Al Si Mn Fe Zn S Eucalipto 560 400<140 160 170   50 <120 20 10 ND 140 Celulignina 500 <60 <140 <40 10 <40<120 <4 <10  <6 <80 normal (1) Celulignina <53  <5  <1 <60 <2 <40 <120<2 <7 <4 <80 limpa (2) Pre-hidroli- 260 370  80 140 65  10  25 20  8  51950  sado (3) (1) cellulignin processed with filtered tap water, withX-rays semi-qualitative analysis (2) cellulignin processed withdeionized, with X-rays semi-qualitative analysis except for K (byICP/AES) and Na (AAS-flame) (3) mass balance not carried out due to theabsence of initial water and washing water analysis.

For gas turbines, specifications of the fuel level are usually made. Inthe case of catalytic cellulignin, due to the purification of thecyclones coupled to the combustor outside the turbine, thespecifications should be made at the level of the combustion gases or interms of an “equivalent fuel”.

The influence of the (Na+K) contents (ppm) on the working temperature ofthe Iconel superalloy 718 is given by:

(Na + K) ppm 0.33 2.28 3.70 4.89 5.65 Temperature (° C.) 927 871 815 760704

The catalytic cellulignin fuel allows operation in the range of 800 to830° C. Coatings are utilized in order to increase the resistance of thesuperalloys to hot corrosion. Table 8 shows the main types of coatingobtained by diffusion (Al, Pt, Rh, NiCrSi) and by overlayers (Co, Cr,Al, Y). Various techniques of depositing the overlayers are utilized,namely: plasma spray, sputtering, deposition of vapor by electronic beam(PVD) and cladding. At present, the hot-corrosion resistances arelimited by the coatings and not by the base-metals of the rotors andstators of the turbines.

The protection with plasma or EB/PVD, however, enables one to achieve16000 h of operation, even under aggressive conditions.

The main requirements for a gas turbine fuel are: calorific power,cleanliness, corrosivity, deposition/obstruction and availability. Thefuel from clean catalytic cellulignin obtained by pre-hydrolysis frombiomass with deionized water meets all the above requirements.

TABLE 9 Protecting Layers (coatings) of the Turbines Capacity in hours;Specification Element Combustion of the in the Deposit Typical chamberProtection Layer technique applications (870° C.) UC Al PC Co Basestators of 870 Al, Si PC Base parts Ni RT-5 Al, Cr DPC Ni Base statorsRT-17 Al, Ni DPC Nickel doped with Thorium RT-19 Al DPC Co Base stators(High temperature service) RT-21 Pt, Al PC Ni stators and rotors 800RT-22 Rh, Al EP/PC Ni base rotors 5000 BB Pt, Rh, EP/PC Ni and Co BaseAl stators and rotors RT-44 Co, Cr, EB/PVD Co Base stators Al, YOverlayers Ni, Co, EB/PVD Overlayers for 7000 (plasma) Cr, Al variousservices 14000 (composed plasma) 18000 (clad) PC—Pack Cementation;DPC—Double Pack Cementation; EP—Eletroplating; EB—Electron Beam;PVD—Physical Vapor Deposition

1. A catalytic cellulignin fuel, characterized in that it is composed ofcellulose and globulized lignin with specific surface of about 1.5-2.5m²/g wherein the catalytic cellulignin fuel has an empirical formula ofC_(5.5)H_(4.2)O_(1.8)N_(tr) and a crystalline density range from 1.252to 1.375 g/cm³.
 2. A catalytic cellulignin fuel according to claim 1,characterized in that it is composed of cellulose and globulized ligninwith an average specific surface of about 2 m²/g.
 3. A cellulignin fuelaccording to claim 1, characterized in that it has a heat combustionvalue of about 18 to 20 MJ/kg.
 4. A cellulignin fuel according to claim1, characterized in that it is ground into particles having size lowerthan 250 mm.
 5. A cellulignin fuel according to claim 1, characterizedin that it presents an ignition time equal to or shorter than 20 ms(0.02 s).
 6. A cellulignin fuel according to claim 1, characterized inthat it has a volatilization temperature of about 350° C.
 7. Acellulignin fuel according to claim 1, characterized by a Na+K contentlower then or equal to 5 ppm.
 8. A cellulignin fuel according to claim1, characterized in that it generates combustion gases with totalparticulates lower than 200 ppm, the particles having diameter lowerthan 5 nm at concentrations lower than 8 ppm.